Thanks for the reply!
As i said, the query works perfectly fine when executed normaly (without $$$ tokens). The data is correct

I should add some details then

When I compare dates in the WHERE clause, I convert them to INTs, just to make sure all the data is consistent. I also do a slightly more complex comparison. I've omitted the details because they're not relevant to my case

anotherDateField BETWEEN CAST(TO_CHAR(dateFieldOne, 'YYYYMM') as int) and CAST(TO_CHAR(dateFieldTwo, 'YYYYMM') as int)

Next, the date format is %TimeStamp, and it's very common in my data. I work with it every day, and every time function you can think of works without a problem

So the time data works fine, the outer WHERE clause doesn't catch up because of $$$RESTRICT in the inner section but without it the listing would not work at all

If it is pure ObjectScript how to write IF ELSE statement in %expression for example? Or can i use RETURN stetement? 

There are situations when you need to return a specific value. The Range expression doesn't work, for example, when you need to determine the display value for Null.

So there's only one way

IF 'value {return "Value is False"} else {return "Value is True"}

But this is wont work

I can still define a class method inside the cube and reference it from within, for example, %cube.CustomLogicClass(%source.DBValue), but that seems redundant. It leaves my cube looking cluttered with simple functions containing only if-else logic.